The invention generally relates to methods and filters for removing nitrate ions from a solution. More particularly, the invention relates to methods and filters for removing nitrate ions from a solution using a polymer including a protonated amine.
Nitrate (NO3−) contamination in surface water and groundwater has become a concern on a global scale since it poses a threat to drinking water supplies and promoting eutrophication. High nitrate concentration in drinking water sources can lead to a potential risk to public health, which could result in many diseases, such as birth defects, spontaneous abortion, increased infant mortality, diarrhea, abdominal pain, vomiting, diabetes, hypertension, respiratory tract infections, changes in the immune system, and methemoglobinemia. Therefore, the World Health Organization (WHO) established the limit for nitrate in drinking water to 10 mg NO3−N/L. Nitrate contaminated water therefore has to be treated to meet the applicable regulation.
The technologies commonly used to remove or reduce NO3− in water treatment processes include chemical denitrification with zero-valent iron, ion exchange, reverse osmosis, electrodialysis, and biological denitrification. However, these current available technologies may not be cost-effective and may generate additional by-products.
Thus, there is a need for more efficient methods and filters to remove nitrate ions from water.